Dredge cutter



Dec. 11, 1923.

. D. E. HUGHES DREDGE CUTTER Filed Nov. 9. 1921 2 Sheets-Sheet 1 Dec. 11, 1923. 1,477,352

D. E. HUGHES DDDDDDDDDD ER Filed Nov. 9. 1921 2 Sheets-Sheet 2 Patented Dec. ll, i923.

FATENT @FFlfiE.

Nil-FED DAVID E. HUG-HES, OF SAN PEDRO, CALIFGRNIA, DEDICATED TO THE PUBLIC, BY

7 ASSIGNMENT.

DREDGE CUTTER.

Application filed November 9, 1921. Serial No. 514,101.

(FILED UNDER THE ACT OF MARCH 3. 1883, 22 STAT. L, 625.)

To all whom it may concern: 7

Be it known that I, DAVID E. HUGHES, Engineer Corps, United States Army, and resident of San Pedro, in the county of Los Angeles and State of California, have invented a new and useful Improvement in Dredge Cutters, of which the following description, in conjunction with the accompanying drawings, is a specification.

The invention described herein may be used by the Government, or any of its ofiicers or employees in prosecution of work for the Government, or by any other person in the United States, without payment of any royalty thereon.

This invention relates to suction dredging machines, more particularly it is directed to an improved type of cutter especially eflicacious for cutting into hard pan or other relatively hard material.

One of theprincipal objects of this invention is to provide a simple and efficient cutter which will enhance the material output and afiord smoother and easier running of the cutter engine when employed in connection with dredges operating in rivers and harbors having beds of exceptionally hard material.

Another object of this invention is to effect an improved cutter designed to prevent any time interval between successive engagements of the blades with the material being dredged whereby excessive variations in torque and the resulting vibrations or jerkings so highly detrimental to the dredge assembly are eliminated.

Other objects of this invention are to furnish a cutter having facilities for materially decreasing the time required for dredging material of the character designated and which will function to reduce the depth of the valueless V shaped dredging grooves.

With these and other objects in view this invention consists in certain novel details of construction, combination and arrangement of the parts to be more particularly hereinafter set forth and claimed.

Briefly stated, this invention consists of a cutter frame equipped with suitable cutter blades, the frame being in the form of a conical frustum and involving a ring adapted to encircle the suction pipe, a nose coaxial with the ring and connected to the latter by a series of dextrorsally spiraled serrated vanes and cutting blades attached to the inner surfaces of the vanes.

Referring more particularly to the accompanying drawings in which corresponding parts are indicated by similar reference characters Fig. 1. Is a side elevation of this improved cutter.

Fig. 2. Is an end view thereof, and

Fig. 3. Is a side elevation of the cutter frame, without the blades. 7 r c When engaged in dredging certain rivers and harbors having beds of exceptionally hard material it was found:

(a) The power of the cutter engine was materially limited and could not be increased without jeopardizing the cutter gear and shaft.

(b) The material dredged was not only difficult to cut but when worked became quite sticky.

(c) Cutters of various designs, although good in other materials, would frequently ball up in this hard pan.

(d) The advance had to be small and the cutting so shallow that but one blade could J be engaged at a time thus producing the greatest variation in torque and excessive vibrations or jerkings damaging to ladder, gearing, cutter engine, steam pipes and spuds.

To produce a cutter capable of meeting the preceding conditions it was deemed advisable:

(at) T0 lessen the torque by effecting a reduction of the cutter radius.

(6) To confine the reductions to the for ward end of the cutter inasmuch as its rear end had to encircle the suction pipe. This limitation, however,proved advantageous as it placed the shortest radius where cutting would be hardest and where it would serve to reduce the depth of the valueless V shaped grooves dredged below the required channel depth.

(a) To equalize the torque as much as 100 practicable by twisting or spiraling the cutters to a degree greater than customary in constructions of this character.

(d) To serrate'the cutterblades for the purpose of avoiding backward and forward movement'of the dredgeproduced by exces'sive spiraling of smooth continuous blades and to impart a moderate twist to the cutting edge of each tooth best suited to the material dredged.

The design resulting from the preceding theories when in use demonstrates their accuracy, as it gave freedomfrom vibrations and jerkings of the dredge smooth and easy running of the cutter engine,'and an increased'output of ap roximately twenty per wflm V "In the illustrated embodiment characterizing this invention there is shown'a cutter frame (1), cast in the form of a conical frusturnand'com'prising a rear ring or rim (2),

a"hub"('3)"coaxially spaced from the'ring and formed with a plurality of radially extendedspo-kes (4:) having downwardly and r'e'arward'ly turned extremities, integral; with the upper ends of conically spiraledblade supporting 'vanes'(5)' the lower extremities o'fwhich are cast integral with-ring (2) as clearly shown in Figures and '3 of the di awings;

rVanes(5) are dextrorsall-y spiraled and I serrated along their upper edgesasat (6) while their innersurface's are formed with a longitudinal seat (7) for a purpose hereiners.

A cutter constructed as outlined with its succession of teeth may be favorably compared to a gang plow, in that eacl'itooth makes its' furrow in'advanceof the next, the hard pan or like material being broken or torn from its bed rath'er'than cut as in the case of cuttersutilizing continuous blades, while themultiplicity of te'eth materially increase the number of points at which the bed isengaged'during each revolution of the cutter "head,'thus avoiding backward and forward movement of the dredge.

To obtain this plow like elfect it is essential to have the foremost teeth of each gang at the rear of the cutter head, that is to say the spiral of the blades is such that their running of the engine, eliminating vibras tion and jerking of the dredge and maintaining its position in the cut-exceptionally well and only reacting against the. spud when the forward or front teeth .and their extensions require renewal or repair- Although, in the foregoing,'certain elements have been referred to, as best adapted to perform the functions allotted to :th'em,it is to be understood that various minor changes with respect to theformation of the blades and means of casting the cutter frame, may be resorted to within the scope of the appendedclaims without departing fromor sacrificing any of the principles' ofthis invention.

Having defined my invention, what I claim is new and wish to secure by Letters Patent'is:

1; A cutter comprising a cutter frame provided with spiral blade supporting vanes, a cutting blade secured to the inner s'urfaceof. each ofsaid vanes and conforming in curvature to the latter, thespiral of the blade being such that its rear travels circumferentiallyin advance of its forwardextremity, i Y

2; A cutter comprising a cutter frame involving a ring, a hub spaced fromthe ring and formed with radially extending spokes, blade supporting vanes spirally arranged .between and interconnecting the ring and ex tremities of the spokes'and a'similarly spiraled' cutting blade secured to each of said vanes, the spiral of the cutting blade being such that its rear travels circumferentially in advance of its forwardextremity.

3. cutter frame involving a ring, a, hub spaced from theringand formed'wi'th radially extending spokes, blade supporting vanes spirally ai' ra'ngedbetweenand interconnecting the ring and extremities of the spokes and a similarly spiraled cutting blade secured to and overlying the inner surface of each of said varies, the spiralofwthe cutting blade being such that its rear travels circumferentially in'advance of its forward extremity. I

4. A cutter frame involving a ring, a hub spaced from the ring and formed with radially extending spokes blade supporting vanes spirally arranged'between andinterconnecting the ring and extremities of the spokes, and a similarly spiraled serrated cutting blade secured to and overlying the surface of each of the vanes, the spiral of each cutting blade being such that its rear travels circumferentially in advance of its forward extremity.

5. A cutter comprising in combination a conical frustum-shaped frame and a plurality of cutting elements supported by the 1 frame, the cutting elements being spiraled so'that their rear travels circumferentially in advance of their forward extremities.

DAVID E. HUGHES. 

